1. Field of the Invention
The present invention relates to window security grates and in particular to security grates which can be opened in an emergency to provide an exit.
2. General Background
The use of bars or gratings over windows has become a common practice to help prevent breakage and to prevent unauthorized entrance into the building by prowlers or burglars who may gain access through windows. A common problem presented by such security devices is that of retaining an exit for inhabitants of the building in the event of an emergency such as fire, while still providing security against unathorized entrance.
Several attempts have been made in the known art to address such a problem.
U.S. Pat. No. 4,019,281 entitled "Quick Release Window Guard" teaches vertical bars welded at their ends to upper and lower horizontal cross bars which are bent rearwardly and secured to a building over a window. One end is loosely hinged to the building with joints near the opposite end held by a hidden bolt. A cable through the cross bars into the building allows for removal of the bolt for opening the bars.
U.S. Pat. No. 3,087,750 entitled "Locking Device For Window Guards" teaches a U-shaped member provided with a crank pin cooperating with a sloted bracket attached to a double ended rod. Raising the U-shaped member and resting it against the window locks the window guard and lowering it by breaking or opening the window unlocks it.
U.S. Pat. No. 4,249,345 entitled "Releasable Window Guard" teaches a latch member which controls the vertical locking mechanism. A guard assembly forms an enclosure around the latch and has two doors, one with a vertical hinge and one with a horizontal hinge.
U.S. Pat. No. 999,682 entitled "Combined Guard And Screen For Windows" teaches a first and second bar fixed to opposite sides of a window frame, a third bar pivotally attached near the second bar, cross bars received by sockets and notches in the three bars and a lock to secure the free end of the third bar to the second bar.
U.S. Pat. No. 1,979,808 entitled "Window Attachment" teaches a frame hingedly attached to a window sill to form a platform when opened and held in the closed position by slots which receive a horizontal frame rod.
U.S. Pat. No. 1,854,153 entitled "Window Guard" teaches a removable stop to limit window sash vertical movement and a grill which bars the opposite path of the window opening in cooperation with the sash stop.
U.S. Pat. No. 4,208,837 entitled "Window Guard Having Boxed Release" teaches a guard element hingedly mounted to a wall adjacent the window with a releasable fastener in a lock housing inaccessible from outside the building when the lock bar is inserted in its latched position.
U.S. Pat. No. 4,263,747 entitled "Window Grille Latch System" teaches a spring loaded latch connected to a foot stirrup by means of cables.